The embodiments of the present invention relate to a light emitting device (LED). The LED is a semiconductor device that converts electric current into light. Since a red LED was commercialized, the red LED, together with a green LED, is used as a light source of electronic devices which includes information communication equipment.
For example, a gallium nitride (GaN) semiconductor, which is a nitride semiconductor, has high thermal stability and a wide bandgap. The GaN semiconductor can be combined with other elements, such as, In and Al to form a semiconductor layer that emits green, blue and/or white lights, and wavelengths of the emitted lights can be easily adjusted, so the GaN semiconductor has been spotlighted in the field of high-power electronic devices, such as LEDs.
A conventional nitride semiconductor LED is formed by combining a blue LED with a fluorescent substance. The fluorescent substance absorbs a part of the blue light to emit light having a color band of green, yellow and/or red. At the present time, such a fluorescent substance has low photoconversion efficiency and low reliability at high temperatures. Further, the fluorescent substance occupies a predetermined space on the blue LED, so a volume of the nitride semiconductor LED may be increased.